The present invention generally relates to electronic surveillance within a telecommunication network. More specifically, the present invention relates to lawfully-authorized electronic surveillance within a telecommunication network.
Law enforcement personnel often require the electronic surveillance of telephone calls involving a particular individual, including when that individual is the calling party and when that individual is the called party. This electronic surveillance is traditionally referred to in the law enforcement community as a “wire tap”.
A telecommunication service provider can be required to provide various types of information for various types of calls when performing lawfully-authorized electronic surveillance. The particular information related to the surveilled call that is provided to the law enforcement authorities is typically specified by such legislation as the Communications Assistance for Law Enforcement Act of 1994 (CALEA). Generally speaking, upon request from a law enforcement authority, a telecommunication service provider needs to provide call-identifying information and call content to the law enforcement authority for calls related to a particular subscriber. Call-identifying information includes, for example, dialing or signaling information that identifies the origin, direction, destination or termination of each communication. Note that the call content can include voice associated with the call (e.g., the content on the bearer channel), but not call content associated with data (e.g., data files or graphics). The type of calls to be electronically surveilled can include, for example, a typical two-party call and a multiple-party call such as a conference call.
Satisfying the requirements for lawfully-authorized electronic surveillance becomes increasingly more difficult as telecommunication networks use increasingly more complicated technologies. Such increasingly complicated technologies include, for example, packet-switching to transport voice and/or data, and various protocols that allow for varied quality-of-service based on the particular level of service to which a subscriber subscribes.
When these more complicated technologies are used by a telecommunication service provider, problems arise relating to, for example, distinguishing between packets associated with the bearer channel (which can be lawfully surveilled under CALEA) and packets associated with other types of information, such as non-voice data content being transmitted (which cannot be lawfully surveilled under CALEA).
Similarly, telecommunication services that provide varied quality-of-service are typically based on packet-switched technologies. In a telecommunication system having at least one network using packet-switch technologies, links can be point to point without having a single place within that packet-switched network through which all packets associated with a surveilled party can electronically surveilled. In other words, a surveilled party can use a telecommunication device at an untrusted location (i.e., not under the service provider's control) yet be connected to a trusted network (i.e., under the service provider's control) that uses packet-switched technology. Consequently, performing lawfully-authorized electronic surveillance within the trusted network that uses packet-switched technology is problematic because no single point exists within that trusted network through which all packets pass.